Fungal Proteolytic Enzymes

Part I. Isolation of two Kinds of Acid-proteases Excreted by Aspergillus niger var. macrosporus

Abstract

Two kinds of proteolytic enzyme, tentatively named acid protease A and B which showed a single peak on electrophoresis individually, were isolated from the crude enzyme powder obtained from the broth filtrate cultured with Aspergillus niger var. macrosporus. Acid protease B is similar too the fungal acid protease previously reported, because the enzyme exhibits optimum activity on milk casein at about pH 2.6 and 55°C when the incubation was done at pH 2.6. Acid protease A is a new proteolytic enzyme, because the enzyme exhibits optimum activity on milk casein at about 2.0 and 70°C or 60°C when the incubation was done at pH 2.6 or 1.5 respectively.